Update PHPStan

[yubiuser]

What does this PR aim to accomplish?:

We've been using phpstan natively in our github workflows. In order to make it work, we needed to set a fixed php version (introduced by #2007). This broke recently, as ubuntu-latest as GH runner updated to 22.04 which ships with php 8.1 instead of 8.0.
To avoid using updating the action with every new ubuntu release, I switched the workflow to use this phpstan action:
https://github.com/php-actions/phpstan

It will continue to use our configuration at phpstan.neon.dist. The optionexcludes_analyse is deprecated and replaced with excludePaths.

Side note: I updated the phpstan version in composer.json from ^0.12.42 to ^1*. The composer.lock is not updated yet, but I'll add composer as environment to dependabot so it should update this as well in the next run.

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[rdwebdesign]

The sudo update-alternatives for PHP was introduced an year ago to fix exactly the same issue, but with different versions.
At that time, using PHP 8.0 was the best choice, but this is not needed anymore.